The objectives of the proposed plan of research are to characterize the metabolites of aromatic nitro compounds which are thought to be responsible for the observed toxicities of those compounds, i.e., carcinogenicity and mutagenicity and to identify the enzyme(s) responsible for their metabolism to: reactive intermediates. The reductive metabolism of two nitro compounds, nitrofurazone and nitrofurantoin, has been investigated. Methodology for the separation of metabolites has been developed using high pressure liquid chromatography. Five metabolites of nitrofurazone have been detected by this method. The metabolite pattern is markedly altered when metabolism is carried out in the presence of the nucleophilic agent cysteine. Current studies are designed to determine if cysteine adducts are formed during nitrofurazone metabolism. Three metabolites of nitrofurantoin have also been isolated and partially characterized by UV absorption spectra and NMR. Mass spectral data is currently being obtained for identification of these metabolites. BIBLIOGRAPHIC REFERENCE: Metabolism of Nitrofurazone, Daniel Goodman, Michele Aufrere, Mary Vore and Frederic Meyers. Federation Proceedings 36: #766, 1977.